A conventional position detection error correcting apparatus corrects detected positions by storing in advance individual frequency components obtained by expanding errors in a Fourier series in a nonvolatile memory, inversely Fourier-transforming the individual frequency components at startup and recording error correction values in a random access memory, and reading out an error correction value for each detected position (refer to Patent Document 1, for example).    Patent Document 1: Japanese Published Patent No. 2543245 (lines 2-14 in right column on page 2, FIG. 1)